Automatic firearm



Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE AUTOMATIC FIREARM tionof Switzerland Application February 21, 1934, Serial No. 712,406 InGermany December 11,1933

6 Claims.

'Ihe invention relates to automatic rearms having means for locking thebreech block to the barrel in breech closing position, said meanscomprising lugs on these parts interlocked by longitudinal and rotativemovements of one of them relatively to the other. An object of theinvention is to provide means operative in dependence on the forwardmovement of the breech block relatively to the barrel suitable for thisinterlock- 10 ing, to automatically couple these two parts with eachother in order to ensure the subsequent rotation to complete theinterlocking. Ano-ther object 'of the invention is to ensure that thebarrel and the breech block shall remain together until the locking lugsengage with oneyanother and so that they cannot be separated prematurelyfrom one another, for instance by recoil.

This arrangement is particularly advantageous for rearms having asliding barrel which, after a shot is fired, is first held firmly in arear retracted position and afterwards moves along with the breech blockwhile the lugs are being interlocked. The coupling device according tothe invention prevents the barrel (which in the case of large calibreweapons is generally provided with a special recuperative device) fromflying forward relative to the breech block, in which event theinter-engagement of the locking lugs which is positively eiected independence on the movements of the barrel and the breech would not bepossible. A further object is to provide a coupling device, which on theinitial preparation and loading of the weapon by hand ensures that thebreech and the barrel shall be held together for a period exceeding thatrequired for the unlocking of the breech from the barrel, whereby thenecessity of timing the action of the barrel retaining catch veryexactly with the' completion of the unlocking operation is avoided.

It is advantageous, in order to ensure that the breech be locked, toutilize the coupling device at the same time as a catch for the barrelin its rear position. The device is then actuated by the breech blockwhen it runs out, the barrel being in its rear locked position, into aposition in which it couples the barrel with the breech block, afterwhich both parts move forwardly together to eifect the locking operationunder the simultaneous action of the barrel running-out spring and theclosing spring. Consequently a relatively Weak closing spring issu'cient and this, particularly inthe case of machine guns of 2 cm.calibre and more, is an advantage in the initial preparation and loadingof the weapon by hand. 'Moreover, those surfaces of the members whichcontrol and eiect the above-mentioned movements of the catch, are soorganized that the held barrel is set in motion somewhat before thebreech block arrives at the end of its forward movement relay tive tothe barrel. The impact of the breech is i5 thus softened and the catchwhich already provisionally couples the barrel and the breech ensuresthat these two parts shall be held together until the inter-engaginglugs, which come into operation on the succeeding common run- 10 ningout movement, assume this function.

The accompanying drawing shows a weapon of the type referred toconstructed according to the invention, in which Fig. 1 is alongitudinal section with the barrel 1'5 and the breech block in theirforward end position, Y Fig. 2 is a longitudinal section with the barreland the breech block in the rear position, the barrel be'ng held, and

Fig. 3 shows a detail of the locking sleeve on an enlarged scale.

The barrel b slidably mounted in the housing a is firmly connected by abayonet catch with the female screw threaded member b1 Vand 25.`A by wayof its thread b2 with the barrel casing b3. In the casing b3 isrotatably mounted a locking sleeve c. The rear end of the barrel casingb3 is provided at the top with a projection b4.

which is embraced by the guide bolt d1, this bolt 30 d1 being subject tothe influence of the barrel running-out spring d. The bolt d1 isdisplaceably mounted in a recess in the housing cover a2 hinged about apin a1. The cover carries, on a projection which forms the abutment forthe running 35 out-spring d, a roller e engaging in a cam groove c1formedin the locking sleeve yc. In the cover a2 there is alsoaccommodated the closing spring f, the spring guide member f1 supportingthe breech block g. The head ofA the breech block g can move i0 forwardinto a correspondingly shaped boring b5 in the barrel casing b3 and itslocking lugs gs engage in the corresponding members c2 on the lockingsleeve c.

The end of the barrel casing is L-shaped as 45`- shown more clearly inFig. 2 and in a recess formed in the foot of the closure there isaccommodated the coupling device according to the in-v vention whichforms at the same time the barrel retaining catch. It consists of alever h adapted 50 to pivot about a pin h2 under the influence of aspring h1, which lever is adapted to co-operate alternately, either, bymeans of the engagement of the front edge ha of its lower surface, in anotch a3 in the housing, to retain the barrel in its reark 55 female nutb1, the barrel casing b3, the pin h2 and the lever h, with the breechblock y.

After a shot has been red, all the Vsliding parts (barrel b, barrelcasing b3, locking sleeve c, and the breech y) move back togetheragainst the action of the barrel running-out spring and the closingspring, until the locking sleeve c, turned by the action of the fixedroller e inthe cam groove c1,

unlocks the breech block g. Shortly afterwardsV the barrel b and theparts connected therewith in consequence, for instance, of impact with aprojection on the housing, come to rest and in this position the notcha3 in the housing a is opposite the front edge h3 of the lever It whichengages therein under the influence of the spring h1. The alreadyunlocked breech block-g is thereby completely freed. The breech blocknow moves further backward alone (Fig. 2). With the expansion of theclosing spring f the breechblock g, if necessary after disengagement ofa V,catch holding it in the rear end position, is then moved-forward,feeding a cartridge into the barrel now held in the rear end positionuntil by the impact of the inclined surface g1 with the lever surfaceh4, the lever h is disengaged from the notch as in the housing andswings its head h5 behind the breech block projection g3. The barrel isthereby liberated and at the same time is coupled tothe breech block gin the longitudinal direction. These parts now move forward togetherunder the influence of the barrel running out spring d and closingspring f, and during this continued movement the roller e engaging inthe cam groove c1 causes the locking sleeve c to turn and the lockinglugs cz to engage with the corresponding members g2 on the breech blockg. Shortly after the complete locking, the barrel and the breech reachtheir front end position inthe housing of the weapon;

The barrel retaining and coupling lever h is of such dimensions that thesurface g1 of the breech block which co-operates with the inclinedsurface h4, disengages it from the notch a3 of the gun housing shortlybefore the breech members strike against the abutment surfaces of thebarrel casing b3. Thus the barrel b under the influence of the barrelrunning out spring d begins its movement into the forward end positionbefore the breech block strikes it, and the impact eifect is furthersoftened by the Vco-operationrof the inclined surfaces g1--h4, and theforward drive thereby exerted on the barrel. In order that the lockinglugs g2 of the breech block may always find room for swinging inlaterally between the counter lugs c2 on the barrel locking` sleeve cthe leading ends of the lugs are bevelled.

We claimz- 1. In an automatic firearm the combination with a housing, ofa barrel, a barrel casing slidable with the barrel in the housing, abreech block slidably mounted in the housing, a spring urging theYbreech bolt towards the breech end of the barrel, lugs on the barrelcasing, lugs on the breech block arranged to interlock with the ysuccessive movements.

` the breech'block towards the breech end of the barrel, lugs on Ythebarrel casing, lugs on the breech blockarranged to interlock with thecasing lugs to close the barrel breech by an axial and a rotary movementin succession of the casing and breech block relatively to each other, acoupling device separaterfrom said lugs for automatically'engaging thecasing with the breech block on completion of such axial movement, andmeans for then effecting said rotarymovement.

3. In an automatic firearm according vto claim l, the arrangement thatthe coupling device in addition Vto automatically engaging the casingwith the breech block also comprises a catch for retaining the barrel inthe position of recoil.

4. In an automatic firearm according to` claim 2, the arrangement thatthe couplingV device in addition Vto automatically engaging the'casingwith the breech block also comprises a catch for retaining the barrel inthe position of recoil.

5. In an automatic rearmthe combinationwith a housing, of a barrel, abarrel casing slidable with the barrel in the housing, a breech blockslidably mounted in the housing, a spring urging the breech bolt towardsthe breech end of the barrel,

lugs on the barrel casing, lugson the breech block arranged to interlockwith the casing lugs to close the barrel breech by successive movementsof the casing and Ybreech block relatively to each other, a leverpivoted in the barrel casing and cooperating' with a notch in thehousing to lock the ba-rrel in recoiled position, and means on thebreech block to swing said lever out of the notch and into'engagementwith the breech block to couple the'- barrel casing therewith inposition permitting their final relative movement to completethe'interlocking of thelugs.

6.7In an automaticv rearm. the combination with a housing, of a barrel,a barrel casing slidable with the barrel in the housing, `a breech,block slidably mounted in the housing, a spring urging the breech bolttowards the breech end of the barrel to interlock with the casing lugsto close -the barrelV breech byan axial and a rotary movement insuccession of the casing and breech block relatively to each other, alever pivoted in the barrel casing and cooperating with a notch in thehousing to lock the barrel in recoiled position, Vand means Yon thebreech block to swing said lever out of the notch and into engagementwith the breech blockto couple the barrel casing therewith in positionpermittingthe said relative-rotary movement to complete the interlockingof the lugs.

Y FI-IJEIODOR` RAKULA..

FRITZ HEIKJ'JPJTI.`

